Orthopaedic screws

ABSTRACT

An orthopaedic screw having a plurality of regions, at least one of which may be porous. The orthopaedic screw includes a head, a tip and at least one thread. The porosity of the screw of the present invention can vary within the part or region, including changes in pore shape, size and density. These characteristics can vary along the length of the screw axis and/or radially (from the outer diameter to the axis). The orthopaedic screw may further include at least one solid region formed of any implantable polymer, reinforced polymer or metal.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a non-provisional application based upon U.S. provisional patentapplication Ser. No. 61/088,383, entitled “ORTHOPAEDIC SCREWS”, filedAug. 13, 2008, which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to orthopaedic devices, and, moreparticularly, to orthopedic screws.

2. Description of the Related Art

A number of solid metal and resorbable polymer (e.g. PLLA, PGA) screwsare known. These screws are generally meant to provide short term (9months or less) attachment of the soft tissue to the bone until healingand integration can occur.

There are a number of problems associated with the known metal andresorbable screws. Due to the density of the metals that are used in thesolid metal screws, it is difficult to examine bone or soft tissue thatis near the screw via x-ray, CT, or MRI scan. The screw causes asignificant ‘white-out’ in the region of the screw. Tissue healing andintegration around the screw is critical to the success of the surgery,thus the ability to evaluate the tissue near the screw is valuable. Inaddition, the solid metal screws have issues with poor initial fixationand later pull-out of the soft tissue (e.g. pull out of an ACL from thebone) does occur. These are painful and can require follow-up surgery.Certainly any improvements to reduce the rate of pull-out and additionalsurgery would be desirable.

With respect to the known resorbable screws, issues with poor initialfixation and pull-out also exist. The rate of resorbtion of the polymercan be difficult to control and can occur too quickly for a givenpatient, increasing the risk of soft tissue pull-out. Further,resorbable materials have been shown to induce fibrous tissue formationbetween the resorbable implant and the bone, increasing the risk of softtissue pull-out. This may be due to the local chemistry created as thepolymer dissolves.

What is needed in the art is an orthopaedic screw that allows for moreeffective fixation of the tissue and visualization with known imagingdevices of the tissue near and surrounding the screw.

SUMMARY OF THE INVENTION

The present invention provides porous screws and screws that can delivertherapeutic agents. Further, the present invention provides a porousscrew for attaching various soft tissues to bone, and/or for attachingbone to bone, and/or for delivering therapeutic agents (for examplebiologics or drugs) to soft tissue and/or bone. Potential uses include,but are not limited to, ACL and PCL reconstruction, medial collateralligament repair, lateral collateral ligament repair, posterior obliqueligament repair, iliotibial band tenodesis reconstruction, patellarligament and tendon repair, pedicle screws for spine repair, bonefracture fixation screw, and drug eluting implant (non-load bearing) fordelivery of therapeutics.

One embodiment of the present invention provides an orthopaedic screwhaving a plurality of regions, at least one of which may be porous. Theorthopaedic screw includes a head, a tip and at least one thread. Theporosity of the screw of the present invention can vary within the partor region, including changes in pore shape, size and density. Thesecharacteristics can vary along the length of the screw axis and/orradially (from the outer diameter to the axis).

The orthopaedic screw of the present invention may further include atleast one solid region formed of any implantable polymer, reinforcedpolymer or metal. The solid region of material may be, for example, atthe outer portion of the threads and the leading tip of the screw due tothe high stresses present during insertion. The solid region may furtherinclude the head of the orthopaedic screw of the present invention.

The materials to create the orthopaedic screw of the present inventioncan be any implantable polymer, metal or ceramic, or any combinationthereof. Possible polymers include polyetheretherketone (PEEK),polyetherketone (PEK), polyaryletherketone (PAEK), polyethylene, andresorbable polymers such as polylactic acid (PLA) and polyglycolic acid(PGA).

The thread of the orthopaedic screw of the present invention may becontinuous or discontinuous and be a single or multiple lead thread. Theinventive screw may further be cannulated or non-cannulated.

The orthopaedic screw of the present invention may further be used tolocally deliver therapeutic agents that promote positive tissue response(e.g. increased growth rate, decreased inflammatory response). Suchtherapeutic agents include, but are not limited to, hydroxyapatite,drugs and biologics.

A second embodiment of the orthopaedic screw of the present inventionprovides for immediate delivery of a therapeutic agent through channelsand/or holes and reservoirs for long-term delivery of a therapeuticagent. Access to the delivery channels, holes and/or reservoirs may begained by provision of a self-sealing polymer diaphragm which can allowfor direct interface with a needle at the time of surgery ofpost-surgery. Alternatively, a removable cap made of PEEK or otherimplantable material may provide access to and seal the medicinedelivery features of the inventive screw.

A third embodiment of the inventive orthopaedic screw composed ofradiolucent material includes a radiopaque marker to indicate positionand orientation of the implant on an x-ray, fluoroscope, or similardiagnostic tool. The markers can be made of any number of more denseimplantable materials. Options include, but are not limited toimplantable metals (stainless steel, titanium, or titanium alloys forexample), barium sulfate filled PEEK, carbon filled PEEK, and otherpolymers with radiopaque material (such as barium sulfate or zirconiumdioxide). Examples of the marker structure include one or more of thefollowing: a pin filling some or all of the cannula of a cannulatedscrew, one of material layers of the inventive screw if manufactured bylayering, all or some of the threads, a cross pin, or the head or tip ofthe screw. The opacity and/or amount of radiopaque material can becontrolled so that the marker does not prevent evaluation of the tissuenear the screw by x-ray or other diagnostic methods.

An advantage of the present invention is that the porous nature of theinventive orthopaedic screw and the ability to deliver therapeuticagents to the surrounding tissue promotes successful tissue integration.Such local delivery of therapeutic agents can aid in such issues asimproving the attachment strength of soft tissue to bone inreconstructive surgeries, improving the attachment strength of bone toscrew, and strengthen bone in osteoarthritic or osteoporotic patients.

Another advantage is that the orthopaedic screw of the present inventioncan effectively be utilized for long term or short term delivery oftherapeutic agents. Another advantage is that the therapeutic agent canbe pre-loaded into the device at the factory or loaded by the surgeonbefore, during or after surgery.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of this invention,and the manner of attaining them, will become more apparent and theinvention will be better understood by reference to the followingdescription of embodiments of the invention taken in conjunction withthe accompanying drawings, wherein:

FIG. 1 is a section view of a porous screw with solid outer threads andtip according to the present invention;

FIG. 2A shows a view of a screw having a continuous thread;

FIG. 2B shows a view of a screw having a discontinuous thread;

FIG. 3 illustrates an implant according to the present invention forimmediate delivery of a therapeutic agent;

FIG. 4 illustrates an implant according to the present invention forimmediate or sustained delivery of a therapeutic agent;

FIG. 5 illustrates a therapeutic agent delivery implant according to thepresent invention with sealing cap;

FIG. 6 illustrates an implant according to the present invention withport attachment features;

FIG. 7A illustrates an implant according to the present inventionincluding a radiopaque marker;

FIG. 7B illustrates an implant according to the present inventionincluding a radiopaque marker; and

FIG. 7C illustrates an implant according to the present inventionincluding a radiopaque marker.

Corresponding reference characters indicate corresponding partsthroughout the several views. The exemplifications set out hereinillustrate embodiments of the invention and such exemplifications arenot to be construed as limiting the scope of the invention in anymanner.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a device which can have a porous natureand which has the ability to deliver therapeutic agents. The porousnature of the device of the present invention and the ability of thedevice of the present invention to deliver therapeutic agentstherethrough addresses existing deficiencies in the known art bypromoting successful tissue integration.

The present invention provides a screw that is porous and/or can delivertherapeutic agents to the surrounding tissue. The materials to createthis screw can be any implantable polymer, metal or ceramic orcombinations of these. Possible polymers include PEEK(Poly(etheretherketone)), PEK (Poly(etherketone)), PAEK(poly(aryletherketone)), polyethylene, and resorbable polymers such asPLA (Poly(lactic acid)) and PGA (poly(glycolic acid)). Likely firstcandidates are PEEK, reinforced PEEK (reinforcing materials include butare not limited to carbon fiber/particles/nanotubes, barium sulfate,zirconia) and titanium/titanium alloys. The screw of the presentinvention can include, but does not need to include, the ability todeliver therapeutic agents (such as drugs or biologics) to thesurrounding tissue. The therapeutic agent can be selected by the surgeonbefore the surgery, at the time of surgery, or at any point in timethereafter. In addition, the therapeutic agent can be pre-loaded intothe device at the factory through currently acceptable practices orloaded by the surgeon before, during, or after surgery (as a follow-upprocedure).

The screw of the present invention can be porous but does not need to beporous.

I. Porous Structure—Design Options According to the Present Invention

Screw 10 of the present invention can be fully porous or have selectregions of solid material. For example, screw 10 may include porousregion 12 and a solid region of material at the outer portion of threads14 and leading tip 16 of screw 10. The solid region of material at theouter portion of threads 14 and leading tip 16 of screw 10 may bedesired due to the high stresses these regions can see during screwinsertion (see FIG. 1). In addition, a very rough porous structure onthe outer portion of the threads can cause insertion of the screw to bedifficult due to its potential to grab versus slide past or cut throughbone/soft tissue. In another example, the head (not shown) of screw 10may be solid. This solid material can be formed of any implantablepolymer, reinforced polymer, or metal.

Thread 14 can be continuous (see FIG. 2A) or discontinuous (see FIG. 2B)and be a single or multiple lead thread.

The porosity of the screw can vary within the region(s), includingchanges in pore shape, size, and density. These characteristics can varyalong the length of the screw axis and/or radially (from the outerdiameter to the axis).

Delivery of Therapeutic Agents

Another way of improving integration of the surrounding tissue is todeliver therapeutic agents that promote positive tissue response (e.g.increased growth rate, decreased inflammatory response). The orthopaedicscrew of the present invention can be used to locally deliver suchtherapeutic agents to the tissue surrounding the device. Such localdelivery of therapeutic agents can aid in such issues as improving theattachment strength of soft tissue to bone in reconstructive surgeries,improving the attachment strength of bone to the screw, and strengthenbone in osteoarthritic or osteoporotic patients. Therapeutic agentsinclude, but are not limited to, hydroxyapatite, drugs, and biologics.

Screws allowing for localized delivery of therapeutic agents, accordingto the present invention, can be, but need not be, porous. Porous screwsaccording to the present invention can, but need not, allow forlocalized delivery of therapeutic agents.

Screw 10 can contain reservoirs 18 for the long-term delivery of thetherapeutic agents, as illustrated in FIG. 4 and/or channels/holes 20,as illustrated in FIG. 3, for immediate, local delivery of therapeuticagents. Screw 10 can further include a plurality of interconnected pores(22) allowing for local delivery of a therapeutic agent to thesurrounding tissue, as shown in FIG. 4. These options are described asfollows:

1. Long Term Delivery.

-   -   a. Reservoirs. One or more reservoirs 18 can allow for the long        term (hours to weeks) delivery of the therapeutic agents. Access        to delivery channels 20, reservoir 18, etc. of screw 10 is        gained by several ways including:        -   i. Self-sealing polymer diaphragm 24 can allow for direct            interface with a needle at the time of surgery or            post-surgery (see FIG. 4).        -   ii. A removable cap 26 made of PEEK or another implantable            material can also provide access to the therapeutic agent            delivery features and seal these features after delivery of            the therapeutic agent (FIG. 5). A tool that facilitates            insertion of the screw could also aide in assembling cap 26            to the screw.    -   b. Connect to another device. Access to the therapeutic agent        delivery features of the screw can be provided by interfacing        screw 10 with a device designed to deliver therapeutic agents        from subcutaneous to elsewhere in the body (e.g. a port that is        frequently used to deliver therapeutic agents from sub-skin to a        vein deeper in the chest cavity). The last option can include        attachment feature 28 on screw 10 that directly interfaces with        port 30, interfaces with catheter 32 (which interfaces with the        port 30) or interfaces with an additional component, which can        be attached to screw 10 to interface with port 30 or catheter        32—See FIG. 6).

2. Immediate delivery. No reservoir is required for this approach. Theaccess means of the reservoir design above (self-healing polymerdiaphragm 24 and removable cap 26) can also be used to access deliverychannels 20 in this design. This design can also include a simpleinterface with a delivery tool. An example of this is a simple slip fitbetween a delivery needle and the screw's cannula.

A given screw can contain any or all of these options.

Cannulation

The screws can be cannulated or non-cannulated.

Radiopaque Markers—Polymer Implants

If the implant according to the present invention is made of aradiolucent material (for example polymers such as PEEK), radiopaquemarkers 34 can be included to indicate position and orientation of theimplant on an x-ray, fluoroscope, or similar diagnostic tool. Markerscan be made of any number of more dense implantable materials. Optionsinclude, but are not limited to, implantable metals (stainless steel,titanium, or titanium alloys for example), barium sulfate filled PEEK,carbon filled PEEK, or other polymers with radiopaque material (such asbarium sulfate or zirconium dioxide). Examples of the marker designinclude one or more of the following: pin 36 filling some or all ofcannula 38 of a cannulated screw, one of the material layers if themanufacturing method involves material layering (discussed below), allor some of threads 14, cross pin 40, or head 42 or tip 16 of the screw(see FIGS. 7A-C). The opacity and/or amount of radiopaque material canbe controlled so that the marker does not prevent evaluation of thetissue near the screw by x-ray or other diagnostic ways (as occurs withcurrent solid metal screws).

II. Porous Structure—Manufacturing Options According to the PresentInvention

The porous structure of the present invention can be manufactured usinga variety of methods. These manufacturing options according to thepresent invention include seven options as follows:

1. Rolled. A porous sheet can be, for example, rolled into a screw. Thisis essentially the reverse of making a radial, spiral cut that isparallel to the axis of the screw. Layers of different materials can becombined in this process. This process involves the following:

-   -   a. Make a porous sheet with holes in a pattern so that they line        up when rolled.    -   b. Roll sheet. This step can be performed with or without the        aid of a center mandrel or rod.        -   1. The sheet can be rolled without the aid of any center            mandrels. This can create a cannulated screw. A            biocompatible pin/rod can be inserted in any center hole and            bonded to the screw to create a non-cannulated screw.        -   2. The sheet can be rolled around a removable mandrel. This            can create a cannulated screw. A biocompatible pin/rod can            be inserted in any center hole and bonded to the screw to            create a non-cannulated screw.        -   3. Alternately the sheet can be rolled around and bonded to            a biocompatible rod, creating a non-cannulated screw.    -   c. Bond the rolled material.

2. Spiraled layers. This method is similar to the rolled approach, butthis method involves bands of material that are wrapped around oneanother. The main difference between this method and that of rolling isthat in this method, the bands of material translate along the axiswhile they are wrapped. Bands of several materials can be combined andintertwined. All bands can have the same direction and pitch of windingor different directions and pitches. These bands can be wrapped around amandrel that is later removed to aid in bonding and to create a cannula.They can also be wrapped around a pin which they are then bonded to,creating a non-cannulated screw. An alternate option for creating anon-cannulated screw is to create the screw with or without the aid of amandrel, then insert and bond a pin within the center hole of the screw.

3. Layered/stacked. Make a number of layers that are stacked and bondedto create the screw. These layers can be parallel to one another. Thefaces of the layers are perpendicular to the axis of the screw, parallelto it, or any other angle of orientation. To reduce secondaryoperations, alignment of one layer to another may be desirable.Alignment of layer to layer can be achieved by such ways as alignmentfixtures that line up the center cannula (if the screw is cannulated) ofeach layer to one another (by way of a pin for example), fixtures orimplant components/features that align pore or thread features to oneanother, or fixtures or implant components/features that align featureson the outer diameter of each layer to one another. Features can also becreated within a given layer to aid in alignment and/or assembly (suchas grooves and mating protrusions).

Note: The holes in options 1-3 can be created by, for example, lasercutting, punching, etching, electrical discharge machining, plasmaetching, electroforming, electron beam machining, water jet cutting,stamping, or machining. For polymer based materials, they can be createdas the sheets are created by, for example, extruding, injection molding,or hot stamping.

4. Dissolvable Material.

-   -   a. One method involves creating a mixture of powdered        implantable material (e.g.

PEEK) and a powder (e.g. salt) that is soluble in something in which theimplantable material is not soluble (such as water, isopropyl alcoholfor the PEEK example). The mixture is then heated to bond theimplantable particles together. Pressure can also be applied to aid inthe bonding of particle to particle. Heat can be created by convectionor other ways (such as coating the powder with a material that absorbs agiven range of energy waves—such as laser waves—and causes heating.(e.g. Clearweld coating by Gentex® Corporation)). Finally, dissolve awaythe filler to create the porous implantable material. This method cancreate net shape parts or raw material shapes from which individualparts can be created.

-   -   b. Another method involves mixing an implantable polymer with a        dissolvable material such as described above. The mixture is        then pelletized and then injection molded to an intermediary or        the final part shape. The filler is dissolved away to create the        porous implantable polymer.

5. Stereolithography.

6. Laser or Electron Beam Sintering of Powdered Material.

7. A combination of the above methods: for example, using thedissolvable method to create microporous sheets of PEEK, then stampinglarger pores and stacking to create a screw.

III. How to Bond Parts Containing Polymer(s)

Options for Bonding Processes

1. Heat. Heat can be generated in several ways:

-   -   a. Ultrasonic welding—use ultrasonic waves to create heat at the        interface of layers.    -   b. Heat staking—use a heated tool to cause melting between the        layers.    -   c. Vibratory welding.    -   d. Laser welding.    -   e. Convection—use an oven to create heat to cause bonding.    -   f. Intermediary layer—for example, use a material that can        absorb energy waves that pass through the polymer (for example        PEEK) without causing damage. The absorbed energy will cause        localized heating. An example of such a coating is Clearweld by        Gentex® Corporation. The laser waves that Clearweld absorbs pass        through the PEEK without causing damage, allowing the layers to        be melted together without large scale damage to the PEEK.

2. Chemical.

-   -   a. Adhesives—a secondary material (such as adhesive) can be used        to bond the material.    -   b. Solvent bonding—a material in which the polymer or reinforced        polymer is soluble can be applied to the sheet surfaces allowing        multiple surfaces to be bonded to one another.    -   c. Overmolding—overmolding of the polymer or reinforced polymer        can provide a chemical bonding

3. Mechanical.

-   -   a. Overmolding—overmolding of a polymer or reinforced polymer        can create a mechanical lock between components on a micro or        macro scale (microscale—the molded material locks with surface        asperities of the existing material. Macroscale—features such as        tongue-groove connections or undercuts). The overmolded material        can be a separate component from the layers or one layer can be        overmolded onto another layer.    -   b. Features are provided within the layers or by a separate        component which provides a mechanical lock—e.g. a pin, snap lock        connection, dove-tail, tongue-groove, rivet, melting tabs to        create a mechanical lock, etc.    -   c. Some adhesives provide a mechanical bond in addition to or        instead of a chemical bond.

4. Combinations of Any/All of the Above Methods.

Order of Processes

1. Bond all layers together at once—especially attractive for methodsutilizing energy waves to trigger bonding (e.g. Clearweld coating byGentex® Corporation or ultraviolet light curable adhesives).

2. Simultaneously bond and roll/stack layers at once—again, may beespecially attractive for methods utilizing energy waves to triggerbonding (e.g. if light cannot penetrate all layers of a rolled design inorder to activate an adhesive, the rolling operation could take place ina light box allowing for a continuous rolling and adhesive curingoperation.

3. Roll/stack layers and bond in increments. This could add a singlelayer at a time or multiple layers.

IV. How to Bond Metal/Metal Alloy Parts

Options for Bonding Processes

1. Heat.

-   -   a. Laser welding—layers can be laser welded in a number of        locations. Two or more layers or wraps of material can be welded        together at once depending on the size of the part and alignment        of the pores (the laser can access several layers to be bonded        through the porosity).    -   b. Spot welding—traditional spot welding can be used to bond two        or more layers/wraps of material.    -   c. Diffusion bonding/sintering.    -   d. Vibratory welding.    -   e. Ultrasonic welding.

2. Adhesives.

3. Mechanical ways. Features are provided within the layers or by aseparate component which provides a mechanical lock—e.g. a pin, snaplock connection, dove-tail, tongue-groove, rivet, melting tabs to createa mechanical lock etc.

4. Overmolding with an implantable polymer. Overmolding of PEEK oranother implantable polymer can create a mechanical lock betweencomponents on a micro or macro scale (microscale—the molded materiallocks with surface asperities of the existing material.Macroscale—features such as tongue-groove connections or undercuts). Theovermolded material can be a separate component from the layers or onelayer can be overmolded onto another layer.

Order of Processes

As with the polymer materials discussed above, two or more layers ofmetal can be bonded during increments or as a continuousstacking/bonding process.

V. Making Threads—Manufacturing Options According to the PresentInvention

1. Form the threads after the layers have been bonded to create a screwblank (see FIG. 13)

-   -   a. Machine the threads    -   b. Hot form the threads with a mold

2. Form threads in the sheets prior to bonding.

-   -   a. Rolling method: The material will not actually create the        complete thread shape until the sheets are formed into the final        shape. Continuous or discontinuous threads can be created.        Design options for this method include creating raised material        that forms the threads or removing material to leave the thread        material. The raised material in the first method can be created        by way of machining, laser ablation, hot stamping, hot or cold        forming, chemical etching, electro-discharge machining and        similar methods. The material of the second method can be        removed by way of machining, laser cutting, stamping, etching,        punching, electro-discharge machining, water jet cutting,        electron beam machining or other means.    -   b. Stacking method: Continuous or discontinuous threads can also        be created by this method. The ‘ears’ of material in each layer        form the threads when the layers are stacked. These can be        created by way of machining, hot stamping, hot or cold forming,        dies/punches, chemical etching, electro-discharge machining and        similar methods.

3. Add separate threads—Threads can be formed separately and attached tothe screw blank. The material for these threads can include:biocompatible polymers, reinforced biocompatible polymers and/orbiocompatible metals. The attachment ways for these threads include:

-   -   a. Mechanical attachment—press/interference fit, tabs.    -   b. Overmolding—mold the solid, porous, or reinforced polymer        screw inside of the solid threads or mold the porous, solid or        reinforced polymer threads onto the already formed screw.    -   c. Adhesive or solvent bonding.

VI. Cannulation—Manufacturing Options According to the Present Invention

With any of the manufacturing methods, screws can be created with orwithout a cannula.

1. Cannulated.

-   -   a. Rolling method. In this method, it can be desirable to wind        the material around a mandrel that is at the center of the        screw, running along its axis. This mandrel can be removed to        leave an open cannula.    -   b. Layered method. A center hole at the axis of each layer is        created to form the cannula when they are stacked together.

2. Non-cannulated.

-   -   a. Rolled method.        -   i. The sheet can also be bonded to the mandrel, with the            mandrel forming a portion of the implant. This mandrel can            be solid or porous and of any implantable material such as            PEEK or titanium.        -   ii. In addition, the material can be formed around a            removable mandrel, creating a cannula. This cannula can be            then be filled with a biocompatible material that is            attached/bonded to the screw.    -   b. Layered method. The layers that are stacked to create the        screw can have solid material in place of the holes that would        create the cannula. Alternately, they can have cut-outs creating        the cannula and this cannula can be filled with a biocompatible        material that is attached/bonded to the screw.

While this invention has been described with respect to at least oneembodiment, the present invention can be further modified within thespirit and scope of this disclosure. This application is thereforeintended to cover any variations, uses, or adaptations of the inventionusing its general principles. Further, this application is intended tocover such departures from the present disclosure as come within knownor customary practice in the art to which this invention pertains andwhich fall within the limits of the appended claims.

1. An orthopaedic device comprising: a screw including a head, a tip andat least one thread, said screw including a plurality of regions, atleast one of said plurality of regions being porous.
 2. The orthopaedicdevice of claim 1, wherein said screw is at least one of an implantablepolymer, metal and ceramic.
 3. The orthopaedic device of claim 2,wherein said implantable polymer is one of polyetheretherketone (PEEK),Polyetherketone (PEK), polyaryletherketone (PAEK), polyethylene,polylactic acide (PLA) and polyglycolic acid (PGA).
 4. The orthopaedicdevice of claim 1, wherein said plurality of regions includes at leastone solid region.
 5. The orthopaedic device of claim 4, wherein said atleast one solid region is at least one of said head, said tip and anouter portion of said at least one thread.
 6. The orthopaedic device ofclaim 4, wherein said solid region is one of implantable polymer,reinforced polymer and metal.
 7. The orthopaedic device of claim 1,wherein said at least one thread is one of continuous andnon-continuous.
 8. The orthopaedic device of claim 1, wherein said atleast one thread is one of a single lead thread and a multiple leadthread.
 9. The orthopaedic device of claim 1, wherein said at least oneporous region includes a plurality of pores, said plurality of poresbeing at least one of different sizes and different shapes.
 10. Theorthopaedic device of claim 1, further comprising at least onetherapeutic agent.
 11. The orthopaedic device of claim 10, wherein saidtherapeutic agent is one of hydroxyapetite, drugs and biologics.
 12. Anorthopaedic device comprising: a therapeutic agent; and a screw havingat least one of channels, holes and a reservoir, said screw configuredto deliver said therapeutic agent to a surrounding tissue when saidscrew is implanted in said tissue.
 13. The orthopaedic device of claim12, wherein said therapeutic agent is one of hydroxyapetite, drugs andbiologics.
 14. The orthopaedic device of claim 12, further comprising aself-sealing diaphragm configured for injection of said therapeuticagent into said screw.
 15. The orthopaedic device of claim 12, furthercomprising a removable self-sealing cap configured for sealing saidscrew after delivery of said therapeutic agent.
 16. The orthopaedicdevice of claim 12, further comprising a port and a catheter, whereinsaid screw is configured to receive said therapeutic agent through saidport.
 17. The orthopaedic device of claim 12, wherein said screw is oneof porous and non-porous.
 18. The orthopaedic device of claim 12,wherein said screw is one of cannulated and non-cannulated.
 19. Theorthopaedic device of claim 12, wherein said screw has opposing sidesand includes a plurality of pores.
 20. The orthopaedic device of claim19, wherein said plurality of pores are interconnected and configured todeliver said therapeutic agent from said screw to said surroundingtissue.
 21. An orthopaedic device comprising: a screw including aradiolucent marker, said screw having a head, a tip and at least onethread.
 22. The orthopaedic device of claim 21, wherein said radiolucentmarker is one of stainless steel, titanium, titanium alloy, bariumsulfate filled polyetheretherketone (PEEK), carbon filled PEEK, and apolymer including one of barium sulfate and zirconium dioxide.
 23. Theorthopaedic device of claim 21, wherein said radiolucent marker is atleast one of a pin, said head, said tip, and said at least one thread.24. The orthopaedic device of claim 21, wherein said screw furthercomprises a plurality of layers.
 25. The orthopaedic device of claim 24,wherein at least one of said plurality of layers is said radiolucentmarker.
 26. Method of localized delivery of a therapeutic agent tosurrounding tissue, the method comprising: providing a therapeuticagent; providing a screw having at least one of channels, holes and areservoir for delivering a predetermined amount of said therapeuticagent to said surrounding soft tissue; and positioning said screw at apredetermined location in the body of a patient.
 27. The methodaccording to claim 26, wherein said therapeutic agent is pre-loaded insaid screw.
 28. The method according to claim 26, wherein saidtherapeutic agent is loaded into said screw one of before, during andafter a surgery.
 29. The method according to claim 28, furthercomprising the step of providing one of a self-sealing polymer diaphragmand a removable cap for direct interface with a needle for loading saidtherapeutic agent into said screw.
 30. The method according to claim 26,wherein said therapeutic agent is one of hydroxyapetit, drugs andbiologics.
 31. The method according to claim 26, further comprising thestep of providing a marker for indicating position and orientation ofsaid screw in said body of said patient.